Feed mechanism for automatic grinding and other machines



Feb. 1 7. 1925. 1,526,542

J. N. HEALD ET AL FEED MECHANISM FOR AUTOMATIC GRINDING AND OTHER MAGFZNES Filed June 10, 1921 2 Sheets$heet 1 Invzniors: JAMES M- HEALD X Feb, 17. 1925. 1,526,542?

J. N. HEALD ET AL.

FEED MECHANISM FOR AUTOMATIC GRINDING AND OTHER MACHINES Filed Jun le, 1921 2,Sheets5ht 2 =nmum,

/ JAMES NHEALD Z l V WALDO J, Gunm i -4 2y%/W%W%.

flitiornm/ Patented Feb. 17, 1925.

UNITED STATES PATENT OFFICE.

JAMES H. HEALD AND WALIDO J. GUILD, OF WORCESTER, MASSACHUSETTS, ASSIGNORS TO THE HEALD MACHINE COMPANY, OF WORCESTER, MASSACHUSETTS, A COR- PORATION OF MASSACHUSETTS.

FIESEID MECHANISM FOR AUTOMATIC GRINDING AND OTHER MACHINES.

Application filed June 10, 1921. Serial No. 476,498.

To all whom it may concern: 4

Be it known that we, JAMEs N. HEALD and WALDO J. GUILD, both citizens of the United States, residing at lYorcester, in

v 6 the county of WVorcester and Commonwealth of Massachusetts, have invented a new and useful Improvement in a'Feed Mechanism for Automatic Grinding and Other Machines, of which the following, together with the accompanying drawings, is

a specification. i The present invention relates to machines, such as grinding machines,- wherein the pieces of work to be operated upon are handled automatically, and presented successively to the operating instrumentality, such for instance as a grinding wheel. The invention is here shown, by way of illustration, in connection with an automatic grinding machine of the general type disclosed in United States Letters Patent to Littman, No. 1,361,883, dated December 14, 1920, this type of machine being adapted for grinding the faces of small fiat articles, 2 such as piston rings or the like. The present invention is designed to effect improvements in machines of this class, by way of securing, rapidly and accurately, the presentation and removal of successive pieces of work to and from the rotatable magnetic chuck which supports each piece in position to be operated upon; the invention also inheres in a-novel means employed to obtain, under all conditions of operation, the properly timed seizure and release of the work by said chuck. The above and other objects are obtained by the construction of mechanism as hereinafter described 'and claimed, reference being had to the accom- 4 panying drawings, in which- Fig. 1 is a diagrammatic plan view of such of the elements of an automatic machine for grinding piston rings as are necessary to illustrate the invention.

Fig. 2 is an enlarged detail plan view of actuating mechanism for the work carrying table.

Fig. 3 is a plan view of mechanism employed for imparting movement to the work carrying table.

-Fig.- 4 is an enlarged detail view of the same mechanism, showing the parts in a different'position.

Fig. 5 is a sectional View of said mechanism, the section being taken on the line 5-5 of Fig. 3.

Fig. 6 is an underside view of the crank disk or plate forming part of said mechalnsm.

Like reference characters refer to like parts .in the different figures.

The machine illustrated in Fig. 1 comprises essentiallya reciprocating head or slide 1, which carries a grinding wheel 2 that is adapted to be moved into and out of contact with work disposed upon and held by a rotating magnetic chuck 3. Such work, as for instance piston rings or other smallarticles to be ground, is adapted to be successively presented to the chuck 3 at times when the head 1 and wheel 2 are in retracted or withdrawn position, leaving the way clear for the movement of the work onto and off of the chuck. As here shown, an intermittently rotated carrier 4 is employed for the transfer of the individual pieces of work from a magazine or supply device 5 to the chuck 3; said carrier 4 provides a circular series of apertures or recesses 7 which, in passing beneath the magazine 5,v withdraw each time the lowermost of the stack of rings or other pieces of work contained by said magazine. This automatic movement of the rings or other pieces onto and off of the chuck forms of itself no part of the present invention, the same being fully disclosed in the machine of'the aforesaid patent to Littman, wherein is employed an intermittently rotating carrier, in all respects similar to the carrier l of Fig. 1. The present invention is 0011- cerned with means employed for procuring the movements of such a carrier, with particular regard to the accurate positioning of the work on the face of chuck 3; it also.

contemplates an automatic and correctly synchronized energization of the chuck in timed relation tothe movement of the carrier, as will'now be described in detail.

Intermittent movement is imparted to the .carrier 4 by means of an arm 8, the latter being pivoted for swinging movement about the axis of rotation of said carrier. At its other end the arm 8 carries a pivoted pawl 9, the latter adapted to engage with suitable fiotches 10, 10 provided in the periphcry of carrier 41.. The. oscillation or vibra tion of the arm 8 through a limited arc is accomplished by its connection to a rotary disk or plate 11, the latter carrying acrank pin 12 from which extends a connecting rod 13, whose other end is Ifivotally attached at 14- to the arm 8. It will be clearly understood'that the movement of the arm 8 to the right in Fig. 1, corresponding to one half a revolution of the plate 11, will cause a corresponding partial rotation of the carrier 4, due to the engagement of pawl 9' with one of the notches 10; on the reverse movement of the arm 8, corresponding to the other half revolution of the plate 11.,

the pawl 9 will. simply slide backward, without effect, on the periphery of said carrier, dropping finally into the next notch 10.

The notches 10 correspond in number and in position to the recesses or apertures 7 7 of the carrier 4; associated with each notch 10 in the periphery of carrier 4- is a V- shaped depression 15, these depressions 15 being adapted for successive cooperation with a wedge shaped point 16 provided by a swingin arm 17. The arm 17 is urged yieldingly toward the periphery of carrier 4 by a spring pressed pin 18, thus prevent- Ling any dislodgmcnt or accidental movement of the carrier in either direction after it has been moved to any one of its predetermined positions of rest. It will be understood tl'iat'when the pawl 9 is again operative to move the carrier forward, the point 16 will be wedged out of the recess 15 by such movement, dropping finally into the next-succeeding recess 15 as said movement is discontinued.

The actuating crank plate 11, by which a step by step movement of the carrier 1 is secured, is itself adapted 'to have intermittent rotation, one revolution at a time, with periods. of dwell alternating with said periods OflDOVGHlGIlli. The operation of said crank plate 11 is controlled by the reciprocations of the grinding head 1. carryin g the rotating grinding wheel 2. .Vhen the head 1 is in its outward or right hand position, thereby disposing the wheel 2 in opera-j ti've relation to the work on chuck 3, the crank plate 11 is held stationary; the movement of the grinding head to the left, Fig. 1, to'withdraw the wheel 2 from the work, after the completion of the grindingof the piece, releases the. crank plate 11 and permits it to make a revolution, thereby procuring one step of the movement of carrier 4-. The means employed inattaining this result will now be described in detail.

The crank plate 11, as shown in Fig. 5, is secured tothe hub of a bevel gear 19, the latter being in mesh with a bevel pinion 20 carried by a shaft 21. On its other end the shaft 21 provides a pulley 22 which is continuously driven by a belt, not shown. The

to withdraw the wheel from the worr. the instant of such engagement, the latch hub of pulley 22 runs loose on the shaft 21 but provision is made for the frictional driving of said shaft by said pulley through the medium, for example, of a pair of friction disks 23, 23, which are keyed to said shaft and which provide suitable frictional surfaces 24,, 24 adapted to engage with the ends of the hub of pulley 22. An adjustable spring plate 25 is employed to yieldingly retain the above named parts in frictional contact, so that the shaft 21 tends always to rotate with the pulley 22, except when a positive obstruction to said rotation is interposed.- 7

Such an obstruction is constituted by a pivoted-latch member 26, having a hooked end 27 adapted to cooperate with a'notch or shoulder 28 on the peripheryof crank plate 11. A spring 29 normally retains the latch member 20 in the positionshown inFig. 3, so as to inter-pose the hooked end 27 in the path of notch or shoulder 28, thereby preventing the clockwise rotation of the crank plate 11 which would otherwise be transmitted from the constantly rotating pulley 22; under. these conditions occurs a slippage 2 is operating upon a piece of work held on v the rotating chuck S.

Upon-the completion of such a grinding operation, the head 1 carrying the grinding wheel is retracted by any suitable mechanism; such mechanism forms no part of the present invention and hence need not be dc scribed in detail. Said grinding head carries a slotted longitudinally adjustable stop plato'izlO which has pivotally secured thereto a pawl or member 31, the latter adapted to engage with a projection 32 of latch memher 2 A spring 33v yieldingly holds said pawl 31 in position to engagesaid projection 32 as the grinding head 1 moves to the left t member 26 is rocked. to carry its hooked end 27 away from notch 28, thereby releasing the crank plate 11 for revolution by the frictional engagement of shaft 21 and pulley 22. The first half of the revolution procures a single step in the movement of carrier l as heretofore described, thus slidingtheground piece of work off of chuck 3' and simultaneously moving onto said chuck another piece of unground' work. This enables the forward right hand movement of the grinding wheel to take-place before a complete revolution of the plate 11 occurs, so that the latch member 26 is freed from the pawl 31, with the result that the hooked end 27 of said latch again en- 28 as the latter completes a gages the notch The parts are thus re- 360 movement.

turned automatically to their original positions in readiness for a repetition of the described action upon the completion of the subsequent grinding operation.

The construction above described lends itself most advantageously to the automatic control of the electric current for the magnetic chuck 3, with the properly timed energizing and deenergizing of said chuck face. For the attainment of these results, the under side of the crank plate 11 is provided with a pair of suitable segmental contact rings 34, 34, which are supplied with current w from a source of electrical energy by brushes 35, 35 of any well known type. Also disposed for contact with the rings 34, 34 are a pair of brushes 36,36 which are connected in circuit with the coilsof the magnetic chuck, the latter having the usual contact rings, shown in dotted lines on Fig. 1, for this purpose. The arrangement is such that during the operation of grinding, the parts are in the positions shown in Fig. 6, so that the coils of the chuck are energized by current supplied from the brushes 35 and flowing through the rings 34 to the brushes 36, thence through the coils of the chuck. Upon completion of the grinding, which is marked by the immediate release of crank plate 11, this circuit is broken because the ends of the rings 34 are carried past the brushes 36. In the absence of residual magnetism, the piece of. work on the chuck 3 is thus rendered free to be moved by carrier 4; in the case of steel pieces, however, the residual magnetism must be counteracted by the use of a pair of contact pieces 37, 37', arranged in line with the respective ring segments 34, 34 andconnected thereto in a crosswise or reverse manner, as shown at 38 in Fig. 6, so that following the breaking of the circuit", there occurs a momentary passage of current in the reverse direction through the coils, thus completely demagnetizing the pole pieces and the work. The chuck remains deenergized until the next piece of work has been moved onto the same and properly centered by the indexing of the carrier as' heretofore described; thereupon, the segmental rings are again brought into posi-' tion by 'the rotation of platell to connect the sets of brushes 35 and 36, thus holding the work firmly on the rotating chuck for the subsequent grinding operation.

It will be seen from the foregoiiig that this construction provides always for the properly timed-making and breaking of the circuit through the chuck coils,regardless of the size or diameter of the pieces of work, and regardless of the length of travel of the grinding head. No adjustments whatsoever are necessary in the positioning of the electrical contact members, since the operation of said members is a function of the carrier movement, as accomplished by a single complete revolution, in every case, of the crank plate 11.

Furthermore, the manner of obtaining the step-by-step carrier movement is conducive to the most favorable operation of said carrier; since each step corresponds to the throw, in one direction, of the crank 12 on plate 11, it follows that the carrier, starting each movement slowly, reaches its maximum speed at the middle of each step, and then slows down gradually,so that there is no appreciable momentum to overcome in bringing it to rest.

We claim 1. In a machine of the class described, a work carrier having a step-by-step movement, operating means for same adapted to retard its speed at the end of each step in combination with means for yieldingly retaining said carrier against movement, in the intervals between successive steps.

2. In a machine of the class described,-a work carrier, a rotatable member adapted to impart step-by-step movement to said carrier, means for retaining said member against rotation, a grinding wheel for operating on said work, and means operable by the withdrawal of said grinding wheel from the work for releasing said member for one complete revolution.

3. In a machine of the class described, a work carrier, a frictionally driven rotatable member adapted at intervals to impart stepby-step movement thereto, means for periodically holding said member against rotation, and means for releasing said memher for single revolutions.

4. In a machine of the class described, a magnetic chuck, a carrier adapted to move work onto and ofl' of said chuck, an intermittently rotated member adapted to impart step-by-step movement to said. carrier, and means carried by said member for energizing and deenergizing said chuck in synchronism with the carrier movement, whereby to release the work prior to its removal from the chuck by the carrier.

5. In a machine of the class described, a magnetic chuck, a carrier adapted to move work onto and olf of said chuck, an intermittently rotatedmember for procuring movement of the carrier and means on said member, for first breaking the chuck circuit, and then procuring the passage therethrough of a demagnetizing current, wherebyto release the work for movement by said carrier.

Dated this eighth day of June, 1921.

JALIES N. HEALD. WALDO J. GUILD. 

